1. Field of the Invention
The present invention relates to a fire detection system employing image processing.
2. Description of the Related Art
A system for detecting a fire using an image processing unit has been disclosed in, for example, Japanese Patent Laid-Open No. 5-20559. The major principle of this kind of system is to sense the flame of a fire by extracting a portion exhibiting a given brightness level from a produced image.
When the fire detection system is installed in a monitored field, for example, a tunnel, light sources having a given brightness level other than flame are as follows:
&lt;1&gt; an artificial light source for illumination (sodium lamp) PA1 &lt;2&gt; a light source on the back of a vehicle (tail lamps or position lamps) PA1 &lt;3&gt; a light source on the front of a vehicle (headlights, halogen lamps, or fog lamps) PA1 &lt;4&gt; a light source on an emergency vehicle (rotating lamp)
These light sources may become causes of incorrect alarming.
An object of the present invention is to provide a fire detection system capable of reliably sensing flame alone using monitoring images while being unaffected by such artificial light sources.